Valve construction and control for powder feed



3, 1968 E. A. HAWK, SR 3,396,746

WAVE CONSTRUCTION AND CONTROL FOR POWDER FEED Filed April 18, 1966 FIG. I.

ATTORNEYS.

United States Patent 3,396,746 VALVE CONSTRUCTION AND CONTROL FOR POWDER FEED Elwin A. Hawk, Sr., East Rochester, Ohio, assignor to Coast Metals, Inc., Little Ferry, N.J., a corporation of of Delaware Filed Apr. 18, 1966, Ser. No. 543,264 13 Claims. (Cl. 137329.05)

ABSTRACT OF THE DISCLOSURE This specification discloses a valve construction for controlling a powder feed. A valve element is located in a housing and extends under a discharge outlet from which the powder drops. The valve element has a rigid core and a resilient covering. The covered portion of the valve element extends through a wall of a passage or chamber in which the powder feed is located. The covered portion of the valve element fits snugly in the opening through the wall and the valve element is supported from the wall of the housing entirely by the resilient covering. The elasticity of the covering holds the valve element normally against the powder feed to prevent powder flow. A portion of the valve element extending outside of the housing is displaced, with resulting compression of the resilient covering which provides a fulcrum for moving the other end .of the valve element away from the powder feed to permit powder flow.

Brief description and background of the invention This invention relates to torches in which powder is supplied to the gas streams within the torch for discharge through the flame jets at the torch tip. The invention relates more particularly to apparatus for controlling the feeding of the powder into the torch.

It is an object of the invention to provide an improved valve construction for controlling the feeding of powder in response to the operation of an actuator which is usually a manually operated handle, but which may be operated by a solenoid or other power means.

Another object of the invention is to provide a simplified valve construction which has a minimum number of parts; is more economical to manufacture; and is more reliable in use.

Still another object of the invention is to provide means for supplying powder to a torch with provision for adjusting the feed to provide a controlled supply which is independent .of the actuator valve and which is adjustable by graduated means that indicate the rate of powder feed. Thus the invention makes possible the provision of a dual control for a powder feed, either by a valve which must be held in open position to continue the feeding of the powder or an adjustable device which can be set according to a scale to supply continuous feed independently of the other control for use with jobs where the torch is used over a long period with a powder supply that should be maintained uniform.

Other objects, features and advantages of the invention will appear or be pointed out as the description proceeds.

Brief description of the drawing In the drawing, forming a part hereof, in which like reference characters indicate corresponding parts in all the views:

FIGURE 1 is a diagrammatic sectional view of a torch having powder feed control means made in accordance with this invention;

FIGURE 2 is a sectional view on the line 2-2 of FIGURE 1;

3,396,746 Patented Aug. 13, 1968 Description of the preferred embodiment FIGURE 1 shows a torch 10 having a body 11 with a tip 12 screwed into one end of the body. A mixer 13 is screwed into the other end of the body 11 and there is a torch handle 14 attached to the mixer 13.

Within the body 11 there is a powder passage 16 leading to an aspirator 18 through which gases flow from the mixer 13 to the tip 12.

The body 11 includes a valve housing 20 which is preferably of one-piece construction with the rest of the body 11. This valve housing 20 has a threaded top opening 22 which is preferably in substantial alignment with the powder passage 16. The valve housing 20 encloses a chamber 24. There is a threaded side opening 26 in one side of the housing 20 and a larger side opening 28 in the opposite side of the housing 20 in substantial alignment with the opening 26.

A fitting 30 screws into the top opening 22 and seats against an O-ring or other gasket 32. This fitting 30 has a discharge outlet 34 at its lower end and the discharge outlet preferably tapers to an expanded cross section at its outlet end to prevent any packing of the powder in the outlet. There is a metering passage 38 through which powder is supplied to the discharge outlet; and a counterbore 39 in the upper part of the fitting 30 has sloping walls where it merges with the metering passage 38 to provide a fair form passage for the powder.

There is a shoulder 40 in the counterbore 39 for supporting a wire gauze screen which covers angularly spaced openings 42 in the side wall of the fitting 30.

A powder hopper 46 has a threaded neck 48 which screws into threads 50 at the upper end of the counterbore 38.

A bushing 52 threads into the side opening 26 of the valve housing 20. This bushing 52 has a hexagonal flange 54 for receiving a wrench. A sleeve 56 fits snugly within the bushing 52, and there is a shaft 58 which fills the interior of the sleeve 56 and which extends somewhat beyond the outer end of the sleeve, as illustrated. The sleeve 56 may be made of rubber or plastic having deformation characteristics similar to rubber. The shaft 58 is preferably made of metal and is rigid.

The sleeve 56 and shaft 58 constitute a valve element which is indicated generally by the reference character 62. The valve element 62 is held against longitudinal displacement in the bushing 52 by friction, since the sleeve 56 is a snug fit in the bushing and the shaft 58 is a similarly snug fit in the sleeve. If desired, the parts can be dimensioned so that the sleeve 56 is actually under substantial compression when the valve element 62 is inserted in the bushing 52. In any event, the sleeve 56 is under some compression as a result of the snug fit.

The bushing 52 is screwed into the side opening 26 until the end of the valve element 62 reaches just beyond the discharge outlet 34 at the lower end of the fitting 30. When the fitting 30 is screwed down against the O- ring 32, the end of the discharge outlet 34 is in firm contact with the valve element 62, as shown in FIGURE 2, and this prevents the escape of powder from the discharge outlet 34. In other words, the valve element 62 is in closed position.

A handle 66 is pivotally connected to a bracket 68 by a fulcrum pin 70. This bracket 68 is integral with the torch body 11 and is shown as being of one-piece construction with the torch body. One end of the handle 66 extends under the outer end'of the shaft 58. The handle 66 is rocked clockwise by pressing down on the portion of the handle 66 which extends over the torch handle 14. This clockwise movement of the handle 66 pushes the outer end of the shaft 58 upward, as indicated by the arrow 74 in FIGURE 3.

Upward movement of the outer end of the shaft 58 compresses the portion of the sleeve 56 which is located between the bushing 52 and the top of the shaft 58. The compression is greatest toward the outer or right-hand end (as viewed in FIGURE 3) of the shaft 58 since this is the end of the shaft which is displaced upwardly.

Resistance to compression of the sleeve 56 toward the inner or left-hand end of the bushing 52 causes the inner end of the shaft 58 to rock downward, as indicated by the arrow 76. This causes some compression of the sleeve 56 against the lower part of the bushing 52 toward the inner or left-hand end of the bushing 52. This rocking movement of the shaft 58 causes the valve element 62 to move away from the end of the discharge outlet 34, as shown in FIGURE 3. This opens a clearance between the fitting 30 and the valve element 62 and permits the escape of powder, as shown in FIGURE 4. By having the distance of the fitting 30 from the right-hand end of the bushing 52 greater, a larger clearance under the fitting 30 can be obtained for any given displacement of the right-hand end of the shaft 58 by the handle 66.

When pressure on the handle 66 is released, the compressed portions of the sleeve 56 at the top of the shaft 58 at the right of bushing 52 and at the bottom of the shaft 58 at the left of bushing 52, expand to their normal condition and restore the valve element 62 to its original closed position shown in FIGURES l and 2.

The opening 28 is closed by a plug 80 which seats against an O-ring gasket 82. This plug 80 can be removed for the purpose of inspecting the valve element 62 and for initially adjusting the valve element axially with respect to the powder discharge outlet 34. The axial adjustment of the valve element is maintained by means of a lock nut 84 which holds the bushing 52 in set position.

When the valve element 62 becomes worn by long repeated contacts with the end of the powder discharge outlet 34, a new working surface for the valve element can be obtained by rotating the valve element to bring a different portion of its circumference into contact with the powder discharge outlet 34. This rotation can be obtained by gripping the valve element tightly and turning it about its axis in the bushing 52, or by turning the bushing 52 in the opening through the wall of the housing. This latter method of adjustment affects the axial adjustment of the valve element, but the change in axial adjustment is very small for the amount of rotation that is necessary to bring a new arc of the circumference of the valve element into contact with the powder discharge outlet.

With the valve element 62 in closed position, the apparatus can be operated to feed powder by turning the fitting 30 in the top opening 22. Such a turning movement in a direction to unscrew the fitting from the valve housing 20 lifts the powder discharge outlet 34 from the valve element 62 and provides the clearance for powder similar to that shown in FIGURE 4. The more the fitting 30 is rotated with respect to the housing 20, the larger the clearance becomes and the faster the powder flows.

FIGURE shows a fixed mark or indicator 88 on the top surface of the valve housing 20, and there are graduations 90 on the cylindrical surface of the fitting 30 for indicating how far the fitting 30 has been turned from the position in which the powder discharge outlet 34 touches the valve element and prevents powder flow.

The position at which no powder flows is indicated by the legend OFF and the other graduations by legends 1, 2, 3, etc. The threads are coarse enough so that there is no occasion to ever turn the fitting 30 more than one revolution. A brake consisting of a rubber or other resilient plug 94 (FIGURE 1) is pressed against the threads of the fitting 30 by a screw 96 screwed into a bore in one side of the housing 20 to provide friction for holding the fitting 30 inany set position corresponding to the various graduations 90.

The openings 42 are for the purpose of venting any pressure build-up that may occur in the powder passage as the result of a flashback or tip blockage when the powder valve is open. The screen in the opening is for preventing escape of powder.

The preferred embodiments of the invention have been illustrated and described, but changes and other modifications can be made, and some features can be used in different combinations without departing from the invention as defined in the claims.

What is claimed is:

1. A valve assembly comprising a valve element having a rigid core and a resilient covering over at least a part of the surface of the core, a housing with a wall and an opening through the wall and through which the covered surface of the valve element extends and in which the said covered surface of the valve element fits snugly, the valve element being supported from the wall of the housing entirely by said resilient covering, the valve element having one end extending outward beyond the wall and having the other end extending inward across at least a part of the width of a chamber in the housing, a passage extending downward into the chamber and terminating in a discharge outlet that contacts with the top of the valve element to close said discharge outlet, and an actuator outside of the housing and having a portion that extends under the outer end of the valve element for lifting that end of the valve element to compress the resilient covering where the valve element passes through the wall of the housing and thereby depressing the inner end of the valve element so that it moves away from the discharge outlet of the passage and thereby ,opens said discharge outlet.

2. The valve assembly described in claim 1 characterized by the core being a shaft and the covering being a sleeve of elastomer material surrounding the outside of the shaft where said shaft passes through the wall of the housing.

3. The valve assembly described in claim 2 characterized by the sleeve extending into the chamber in the housing and constituting the part of the valve element that contacts with the discharge outlet.

4. The valve assembly described in claim 3 characterized by the valve element being rotatable about its longitudinal axis so as to bring different surfaces of the valve element into contact with the discharge outlet to provide a fresh surface of the valve element to replace a surface worn by continued use of the valve.

5. The valve assembly described in claim 4 characterized by the shaft of the valve element being of round cross section with the rigid core of the valve element, where it passes through the wall, having a diameter substantially greater than the radius of the opening through the wall, and the longitudinal axis of the shaft extending substantially normal to the axis of the discharge outlet.

6. The valve assembly described in claim 1 characterized by a powder passage located above the level of the valve, and a passage leading from the powder passage and at least the lower part of which constitutes the discharge outlet.

7. The valve assembly described in claim 6 characterized by the passage immediately adjacent to the discharge outlet having a tapered cross section which increases as the passage approaches the valve element for facilitating free flow of powder from the passage promptly upon movement of the valve element away from the discharge outlet.

8. The valve assembly described in claim 6 characterized by the resilient covering extending across the portion of the valve element that contacts with the discharge outlet to provide a soft seat for the discharge outlet against the surface of the valve element.

9. The valve assembly described in claim 1 characterized by the shaft extending through a fitting which threads through the opening in the wall of the housing, the fitting being rotatable to advance the valve element axially with respect to the wall and with respect to the discharge outlet for adjusting the valve with respect to the discharge outlet.

10. The valve assembly described in claim 1 characterized by the passage having the discharge outlet extending through a fitting which is adjustable in the housing toward and from the valve element to control the contact pressure between the valve element and the discharge outlet when the valve element is in closed position.

11. The valve assembly described in claim 1 characterized by means for adjusting the valve element with respect to the discharge outlet, and an opening through a wall of the housing opposite to the wall through which the valve element extends for inspection of the interior of the chamber in the housing and the valve element and discharge outlet, and a closure movable into position for closing the inspection opening through the wall of the housing.

12. The valve assembly described in claim 1 characterized by an upper powder passage leading downward from a location on top of the housing and having an outlet that communicates with the discharge outlet in the housing, said discharge outlet being movable toward and away from the valve element to control the flow of powder without moving the valve element, and an angularly movable element connected with the discharge outlet and operable to move said discharge outlet toward and away from the valve element.

13. The valve assembly described in claim 12 characterized by the angularly movable element being a fitting that connects the upper powder passage with the housing and that threads into the housing, the discharge outlet being connected with the lower end of said fitting, and the movement of the discharge outlet toward and away from the valve element being effected by screwing the fitting one way or the other in said threads, the outside surface of the fitting having a portion adjacent to a surface of the housing, one of the surfaces having indicia thereon and the other surface having an indicator for showing the position of the fitting and the discharge outlet with respect to the valve element.

References Cited UNITED STATES PATENTS 12/1940 Franck 251-290 X 8/1956 Fogg et a1 137-329.05 

